/* =========================================================
   Jiexuan Zhang — academic homepage
   Layout & interactivity ported from jyfu-vcl.github.io,
   extended with per-publication thumbnails.
   ========================================================= */

* { box-sizing: border-box; }

html { background-color: #f3f4f6; scroll-behavior: smooth; }

body {
    font-family: Georgia, "Source Serif Pro", serif;
    color: #1a1a1a;
    background-color: #ffffff;
    margin: 0 auto;
    max-width: 1000px;
    padding: 0 40px 60px;
    line-height: 1.5;
    box-shadow: 0 0 40px rgba(0,0,0,0.05);
}

img { max-width: 100%; border: none; }

a { color: #527bbd; text-decoration: none; transition: color 0.2s; }
a:hover { color: #2f6fb0; text-decoration: underline; }

h1, h2, h3 {
    color: #2a3f6b;
    margin: 1em 0 0.3em;
    padding: 0.3em 0 0.2em;
    line-height: 1.1;
}
h2 {
    font-size: 1.35em;
    border-bottom: 2px solid #527bbd;
    padding-bottom: 0.3em;
    margin-top: 1.8em;
}
h3 { font-size: 1.08em; color: #3a5ba0; margin-top: 1.2em; }
h1 { font-size: 2em; margin-bottom: 0.1em; }

p  { margin: 0 0 0.7em 0; }
ul { padding-left: 1.2em; list-style-type: square; }
li { margin-bottom: 0.4em; }

.author-name { color: #2f6fb0; font-weight: bold; }
.name-cn { color: #2f6fb0; font-weight: bold; font-size: 1em; margin-left: 0.35em; }

section { scroll-margin-top: 70px; }

/* ---------- Sticky top navigation ---------- */
.topnav {
    position: sticky;
    top: 0;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid #e0e4ea;
    z-index: 100;
    margin: 0 -40px 20px;
    padding: 10px 40px;
    display: flex;
    gap: 20px;
    font-size: 0.95em;
    align-items: center;
    flex-wrap: wrap;
}
.topnav a {
    color: #2a3f6b;
    font-weight: 500;
    padding: 4px 2px;
    border-bottom: 2px solid transparent;
    transition: border-color 0.2s, color 0.2s;
}
.topnav a:hover,
.topnav a.active {
    color: #2f6fb0;
    border-bottom-color: #2f6fb0;
    text-decoration: none;
}
.topnav .nav-name { font-weight: bold; margin-right: auto; color: #2f6fb0; }

/* ---------- Header / hero ---------- */
.hero {
    display: flex;
    gap: 30px;
    align-items: center;
    padding-top: 1.2em;
    padding-bottom: 0.5em;
}
.hero-photo-wrap {
    flex-shrink: 0;
    width: 200px;
    align-self: stretch;
    display: flex;
}
.hero-photo {
    width: 100%;
    height: 100%;
    min-height: 200px;
    object-fit: cover;
    border-radius: 8px;
    box-shadow: 0 4px 14px rgba(0,0,0,0.15);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.hero-photo-wrap:hover .hero-photo {
    transform: scale(1.02);
    box-shadow: 0 6px 20px rgba(47,111,176,0.25);
}
.hero-about {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
}
.hero-about h1 { margin-top: 0; }
.hero-meta { color: #555; margin-bottom: 0.85em; }
.hero-bio { margin-bottom: 0.6em; }
.hero-about .socials { margin-top: auto; padding-top: 0.75em; }

#research > h2 { margin-top: 1em; }

.socials a {
    display: inline-block;
    margin: 0 4px 4px 0;
    padding: 6px;
    border-radius: 6px;
    color: #2a3f6b;
    transition: background-color 0.2s, transform 0.2s, color 0.2s;
}
.socials a:hover {
    background-color: #e9f2fb;
    color: #2f6fb0;
    transform: translateY(-2px);
}
.socials svg { width: 26px; height: 26px; vertical-align: middle; display: block; }

/* ---------- Tabs (Papers / Proposals) ---------- */
.tab-bar {
    display: flex;
    gap: 0;
    border-bottom: 2px solid #e0e4ea;
    margin: 0.5em 0 1.2em;
}
.tab-btn {
    background: none;
    border: none;
    font-family: inherit;
    font-size: 1em;
    color: #3a5ba0;
    padding: 10px 20px;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: color 0.2s, border-color 0.2s, background-color 0.2s;
}
.tab-btn:hover { background-color: #e9f2fb; color: #2f6fb0; }
.tab-btn.active {
    color: #2f6fb0;
    border-bottom-color: #2f6fb0;
    font-weight: bold;
}
.tab-panel { display: none; animation: fadein 0.3s ease; }
.tab-panel.active { display: block; }

@keyframes fadein {
    from { opacity: 0; transform: translateY(4px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ---------- Publication cards ---------- */
.pub-list {
    list-style: none;
    padding: 0;
    display: grid;
    gap: 12px;
    margin: 0 0 1.2em;
}
.pub-item {
    display: flex;
    align-items: center;
    gap: 18px;
    padding: 14px 18px;
    border: 1px solid #e0e4ea;
    border-left: 4px solid #d9dee6;
    background-color: #ffffff;
    border-radius: 6px;
    cursor: pointer;
    transition: border-color 0.2s, background-color 0.2s,
                transform 0.2s, box-shadow 0.2s;
}
.pub-item:hover {
    border-color: #bcd9f0;
    border-left-color: #2f6fb0;
    background-color: #f1f7fc;
    transform: translateY(-2px);
    box-shadow: 0 4px 14px rgba(47,111,176,0.12);
}
.pub-item.active {
    border-color: #2f6fb0;
    border-left-color: #2f6fb0;
    background-color: #e9f3fc;
    box-shadow: 0 6px 20px rgba(47,111,176,0.22);
    transform: translateY(-2px);
}

/* thumbnail (extension over jyfu's design) */
.pub-thumb {
    width: 160px;
    height: 96px;
    flex-shrink: 0;
    object-fit: cover;
    border-radius: 5px;
    border: 1px solid #e0e4ea;
    background: #f7f8fa;
    transition: transform 0.3s ease;
}
.pub-item:hover .pub-thumb { transform: scale(1.03); }
.pub-content { flex: 1; min-width: 0; }

.pub-item .pub-tag {
    display: inline-block;
    background: #e8edf5;
    color: #2a3f6b;
    font-size: 0.78em;
    font-weight: bold;
    padding: 2px 8px;
    border-radius: 3px;
    margin-right: 8px;
    letter-spacing: 0.5px;
    transition: background-color 0.2s, color 0.2s;
}
.pub-item:hover .pub-tag,
.pub-item.active .pub-tag { background: #d8eafb; color: #2f6fb0; }
.pub-title {
    font-weight: bold;
    color: #2a3f6b;
    transition: color 0.2s;
}
.pub-title:hover { color: #2f6fb0; text-decoration: underline; }
.pub-item.active .pub-title { color: #2f6fb0; }
.pub-authors { display: block; margin-top: 4px; font-size: 0.95em; }
.pub-venue { font-style: italic; color: #555; }
.pub-links { margin-left: 6px; font-size: 0.9em; }
.pub-links a { margin-right: 4px; }

/* Status badges for publications */
.badge {
    display: inline-block;
    font-size: 0.72em;
    font-weight: bold;
    padding: 2px 7px;
    border-radius: 10px;
    margin-left: 6px;
    letter-spacing: 0.3px;
    vertical-align: middle;
}
.badge-conf    { background: #e8e0ff; color: #4a2f9e; }
.badge-preprint{ background: #f2e4d9; color: #8a4a1a; }
.badge-first   { background: #d8eafb; color: #2f6fb0; }
.badge-ccfa    { background: #e8e0ff; color: #4a2f9e; }
.badge-ccfb    { background: #e0ecff; color: #1f4a8a; }

/* ---------- Education / career list ---------- */
.edu-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 14px; }
.edu-item {
    display: grid;
    grid-template-columns: 160px 1fr;
    gap: 22px;
    align-items: center;
    padding: 18px 16px;
    border: 1px solid #e8ebf0;
    border-radius: 8px;
    background: #fafbfc;
    transition: background-color 0.2s, border-color 0.2s, box-shadow 0.2s;
}
.edu-item:hover {
    background-color: #f1f7fc;
    border-color: #d4e4f4;
    box-shadow: 0 2px 10px rgba(47,111,176,0.08);
}
.edu-logo-wrap {
    width: 160px;
    height: 96px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 8px;
    background: #f7f8fa;
    border: 1px solid #e0e4ea;
    border-radius: 5px;
    transition: transform 0.3s ease;
}
.edu-logo {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
    transition: transform 0.3s ease;
}
.edu-item:hover .edu-logo-wrap { transform: scale(1.03); }
.edu-body { min-width: 0; }
.edu-row {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 16px;
    margin-bottom: 0.35em;
}
.edu-org { color: #2a3f6b; font-size: 1.12em; }
.edu-degree { color: #333; font-size: 1.02em; margin-bottom: 0.25em; }
.edu-detail { color: #666; font-size: 0.95em; line-height: 1.45; }
.edu-date { color: #777; font-size: 0.95em; white-space: nowrap; flex-shrink: 0; }

/* Career: square company logos */
#career .edu-logo {
    object-fit: contain;
}

/* ---------- Footer ---------- */
.footer {
    text-align: center;
    font-size: 0.88em;
    color: #808080;
    border-top: 1px solid #e0e4ea;
    margin-top: 3em;
    padding-top: 0.8em;
}

/* ---------- Responsive ---------- */
@media (max-width: 700px) {
    body { padding: 0 20px 40px; }
    .topnav { margin: 0 -20px 16px; padding: 10px 20px; gap: 14px; }
    .hero { flex-direction: column; align-items: stretch; }
    .hero-photo-wrap { width: 100%; align-self: auto; max-width: 240px; margin: 0 auto; }
    .hero-photo { min-height: 220px; max-height: 280px; }
    .hero-about { width: 100%; text-align: left; }
    .hero-about .socials { margin-top: 0.75em; }
    .pub-item { flex-direction: column; align-items: stretch; }
    .pub-thumb { width: 100%; height: 160px; }
    .edu-item { grid-template-columns: 1fr; gap: 14px; }
    .edu-logo-wrap { width: 100%; height: 120px; }
    .edu-row { flex-direction: column; align-items: flex-start; gap: 4px; }
}